The present disclosure relates to heaters for heating a liquid. More particularly, the disclosure relates to an inline heat exchanger which can be used to heat a corrosive fluid. If desired, a gas purge can also be used.
It is known to use a purge gas to remove permeate from a heater assembly in order to protect a metal heat exchanger surface. A patent pertaining to such an arrangement is entitled “Gas purged flexible cable type immersion heater and method for heating highly corrosive liquids”, U.S. Pat. No. 4,553,024. Another similar patent is entitled “Purged grounded immersion heater”, U.S. Pat. No. 5,875,283. The subject matter of both of these patents is incorporated hereinto by reference in their entirety. Both patents utilize a purge gas to remove permeate from the inside of a fluoropolymer tube encasing a heating element. The first element is a simple resistance wire heating coil. The second is a metal encased heating element which provides a ground plane for added safety.
It would be desirable to reduce the amount of expensive fluoropolymer materials which are employed in the existing designs, while still being able to perform the same functions. It would also be desirable to provide heat exchanger tubes aligned in a radial array in order to maximize the area per unit volume and allow for simplified assembly of the unit. It would further be desirable to maintain an uninterrupted flow path through the heat exchanger in order to provide the highest purity of the process fluid, i.e., the fluid which is being heated.